Predictive cloud-based presimulation

ABSTRACT

Embodiments related to predictive cloud-based presimulation are described herein. For example, one disclose embodiment provides, on a computing device, a method comprising receiving an input of state from a client device and executing a server simulation of a digital experience based on the input of state, the server simulation configured to run concurrently with, and ahead of, a client simulation on the client device. The method further comprises generating a plurality of simulation results from the server simulation, selecting one or more simulation results from the plurality of simulation results based on a likelihood the client simulation will utilize a particular simulation result, and sending the one or more simulation results to the client device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 13/494,806, filedJun. 12, 2012, the entirety of which is hereby incorporated herein byreference for all purposes.

BACKGROUND

Cloud-based services allow network-connected devices to leveragecapabilities that may not be available on the devices due, for example,to cost, size, and/or power consumption considerations. Such servicesmay be used, for example, in a video game environment to leverage thegreater computing resources of a cloud-based game server. However, insome situations, the user experience may be impacted by networkperformance. As such, users may experience noticeable lag or degradationin simulation quality.

SUMMARY

Embodiments related to predictive cloud-based presimulation aredisclosed herein. For example, one disclose embodiment provides, on acomputing device, a method comprising receiving an input of state from aclient device and executing a server simulation of a digital experiencebased on the input of state, the server simulation configured to runconcurrently with, and ahead of, a client simulation on the clientdevice. The method further comprises generating a plurality ofsimulation results from the server simulation, selecting one or moresimulation results from the plurality of simulation results based on alikelihood the client simulation will utilize each of the one or moresimulation results, and sending the one or more simulation results tothe client device.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of an example digital experience utilizingpredictive cloud-based presimulation.

FIG. 2 shows an embodiment of an example use environment for providingpredictive cloud-based presimulation of a digital experience.

FIG. 3 shows a process flow depicting an embodiment of a method forproviding predictive cloud-based presimulation.

FIG. 4 shows a process flow depicting an embodiment of a method forexecuting a client simulation of a digital experience utilizingpredictive cloud-based presimulation.

FIG. 5 schematically shows an example embodiment of a computing system.

DETAILED DESCRIPTION

As network connectivity has become commonly available for computingdevices ranging from smart phones and tablet computers to gamingconsoles and set-top boxes, cloud-based services have likewise becomeincreasingly available. Cloud-based services may allow network-connecteddevices executing a digital experience to offload all or part of acomputing task to the service, thereby leveraging potentially greatercomputing resources of the cloud-based service. The term “digitalexperience” as used herein refers to any user experience produced byexecution of computer-readable instructions. Examples of digitalexperiences include, but are not limited to, video games and otherinteractive media experiences (e.g. interactive television), as well asnon-game and/or non-media experiences (e.g. productivity applicationssuch as word processors, presentation editing and/or playback programs,etc.). It will be understood that these embodiments of digitalexperiences are presented for the purpose of example, and are notintended to be limiting in any manner.

In some scenarios, an entire digital experience may be executed by acloud-based service, and a rendered digital experience (e.g., audio,video, etc.) is transmitted to the client device for presentation. Sucha configuration may reduce the performance requirements of the clientdevice. However, latency arising from the network connection between thedevice and the server may be noticeable when responding to user inputs,which may offset any performance benefits offered by the resources ofthe cloud-based service.

In other scenarios, execution of the digital experience may bedistributed across both the client device and the cloud-based service,such that the client handles some portions of the digital experience,and the server handles other portions. However, the implementation ofsuch distributed execution of a digital experience may involve makingdecisions during development as to which portions of the experience areto be offloaded to the server system. Such an approach may betime-consuming, and may result in an inflexible system in light ofpotential fluctuations in network and/or hardware performance. Further,such an approach may not be readily useable with existing digitalexperiences.

Thus, embodiments are disclosed herein that relate to intelligently andadaptively distributing tasks between a client and a cloud-basedservice. While participating in a digital experience, a user may becapable of influencing a small portion of the overall digital experience(e.g., immediate area near a virtual character) at any given time. Thedisclosed embodiments may automatically identify via a predictivemechanism those portions of a digital experience that are not likely tobe readily influenced by user actions, and provide those portions of thedigital experience via the cloud-based service for presentation by theclient. Portions that are likely to be influenced by user actions may beexecuted locally on the client.

The portions of the digital experience to be provided by the cloud-basedservice and transmitted to the client may be identified in any suitablemanner. In some embodiments, as described in more detail below, acloud-based presimulation may be executed concurrently with, and aheadof, a client-based simulation. Results from the cloud-basedpresimulation may be selectively sent to the client for use by theclient simulation based upon a likelihood that a presimulation resultwill be utilized by the client. As used herein, the term “presimulation”refers to a simulation on the server system configured to executeconcurrently with, and ahead of, a client simulation executing on theclient device. Such a predictive mechanism may provide for efficient andadaptable distribution of a simulation between a client and acloud-based service, and may be applied to existing digital experienceswhich utilize deterministic simulations (i.e. simulations in which asame outcome is produced by a same input, even if performed at adifferent time).

FIG. 1 shows an embodiment of a digital experience 100 in whichpredictive cloud-based presimulation may be utilized. A first-personcombat video game scenario is presented for the purpose of example, butit will be understood predictive cloud-based presimulation may be usedwith any other suitable digital experience. Digital experience 100 isdisplayed on a computing device display (e.g. a television, monitor,mobile device screen, head-mounted display, and/or any other suitabledisplay device), and comprises primary elements 101, 102 and 104,illustrated as virtual character, a weapon and a muzzle flash,respectively, wherein the term “primary” indicates elements that aredirectly controlled via user input. For example, the movement of thevirtual character 101 and the weapon 102 may substantially mirror motionof a game controller or user body part gesture, and the muzzle flash(element 104) may be displayed upon user-actuation of a “fire” button.As elements 101, 102 and 104 are affected by user inputs and players mayexpect immediate feedback to user inputs, elements 101, 102 and 104 maybe examples of portions of digital experience 100 that may be desirableto render locally on a client device to avoid network latency.

Digital experience 100 further comprises elements 106 and 108,illustrated as a tree and an enemy tank, respectively, that may beaffected by manipulation of the primary elements, but are not as likelyas the primary elements to be affected. For example, the tree (106) orthe tank (108) may be configured to explode upon impact of a projectilefired from the weapon (102). Such elements may be referred to herein forconvenience as “secondary elements.”

Digital experience 100 further comprises elements 110 and 112,illustrated as sky and mountains, respectively, that are far away fromthe virtual character (101) and/or otherwise unlikely to be affected bymanipulation of the primary elements. Such elements may be referred toherein for convenience as “tertiary elements.” Secondary elements 106and 108 and tertiary elements 110 and 112 may be examples of elementswell suited for cloud-based presimulation, as discussed in more detailbelow.

During progression of digital experience 100, the likelihood of userinteractions affecting a selected element of digital experience 100 mayvary during use. For example, in the illustrated example, as the virtualcharacter 101 moves towards element 106, bullets fired by the player maybe more likely to strike element 106 and cause display of a bullet hit.As such, the portions of the digital experience that are executed on thecloud-based service and sent to the client may vary during the course ofthe digital experience as the likelihood of user actions affecting theportion changes, as discussed in more detail below.

FIG. 2 shows an embodiment of an example use environment 200 forproviding predictive cloud-based presimulation of a digital experience.Environment 200 comprises one or more client devices 202, illustrated asan arbitrary number N of client devices. Environment 200 furthercomprises server system 204 in communication with client devices 202 viacomputer network 206 (e.g., the Internet). It will be understood thatnetwork 206 may comprise any suitable combination of networks and/orsubnetworks without departing from the scope of the present disclosure.

Client device 202 may be configured to execute a simulation 208 of adigital experience (e.g., digital experience 100). In some embodiments(e.g., thin client scenarios), client device 202 may be configured tolocally execute a lower-quality digital experience (e.g., lower framerate, lower resolution, compressed audio, etc.).

In order to provide a higher quality digital experience, server system204 may be configured to operate a cloud-based service configured toexecute a server simulation 210 concurrently with, and ahead of, clientsimulation 208, such that server system 204 presimulates the digitalexperience. Presimulation may allow server system 204 to predictinformation likely to be used by client device 202, and to thereforeprovide said information to client device 202 ahead of the use of theinformation by client device 202. This may help to utilize comparativelygreater computing resources of server system 204 for the benefit ofclient device 202 while avoiding network latency.

As a more specific example, during presentation of the digitalexperience by a client device, when a function call occurs, the clientdevice may first check for high-quality pre-simulation results fromserver simulation 210 corresponding to the particular called functionand set of inputs for the called function. If results corresponding tothat function call and set of inputs have been previously received fromthe cloud-based service, then the client device may use thehigher-quality server simulation results without executing the functioncall locally.

On the other hand, if results corresponding to that function call andset of inputs have not been previously received from the cloud-basedservice (e.g. where the cloud-based service elected not to send thoseparticular results or the results failed to reach the client), then theclient may execute the function call to produce lower-quality simulationresults. In this manner, the lower-quality simulation on the clientdevice may provide a “fallback” option in rendering the digitalexperience. It will be noted that the portions of the digital experiencethat are affected by user actions (e.g. muzzle flash 104 of FIG. 1) maybe relatively small portions of the overall experience. Thus, asubstantial portion of the overall user experience may be produced bythe higher-quality simulation provided by the cloud-based service, whilethe lower-quality portions may have a relatively small presence in theoverall experience. It further will be understood that these scenariosare presented for the purpose of example, and that client simulation 208and server simulation 210 may comprise any suitable configurationwithout departing from the scope of the present disclosure. For example,in other embodiments, simulations 208 and 210 may be executed at similarquality.

To help to ensure that results from the server simulation 210 arerelevant to the client simulation 208, client device 202 may beconfigured, upon receipt of user input, to provide information regardingsaid input to server simulation 210. Server simulation 210 may thus beconfigured to “rewind” to the state (e.g., frame) associated with theinput and to re-initialize the simulation based on the state. It will beunderstood that the state of a digital experience may be represented bya relatively small amount of data. For example, in some embodiments,client device 202 may be configured to provide an input of statecomprising the state of a user input device used to control the digitalexperience (e.g. a video game controller). In such embodiments, thestate may be represented by, for example, eight bytes or less. Wheresuch a digital experience is provided at 30 frames per second, the stateprovided to the cloud-based service from the client may utilize amaximum of 240 bytes per second to represent the user input, therebyutilizing a small amount of upstream bandwidth.

Due to server simulation 210 executing ahead of client simulation 208,not all server simulation results 212 may ultimately be used by clientsimulation 208. For example, user inputs received at the client mayalter the course of the client simulation relative to the serversimulation. As such, and in light of the overhead associated withgenerating results 212 and transmitting said results to client device202, it may be desirable not to send all of the server simulationresults to client device 202.

Accordingly, as mentioned above, server system 204 may be furtherconfigured to apply one or more metrics to server simulation results 212in order to select simulation results 214 to send to client device 202.For example, server system 204 may be configured to determine alikelihood 216 that client simulation 208 will utilize a particularserver simulation result 212, and may determine whether to send aparticular server simulation result based upon the determinedlikelihood.

Likelihood 216 may be determined in any suitable manner. For example,likelihood 216 may be determined via statistics regarding the outcome ofre-simulation of previous simulation results. As described above, uponreceipt of an input of state from client device 202, server system 204may be configured to re-initialize server simulation 210 to reflect saidinput of state. Resimulation may result in one or morepreviously-produced simulation results 212 being invalidated. Suchstatistics may therefore comprise data regarding how often there-simulation produces a same or different result as a previoussimulation.

Server system 204 may be further configured to select one or moresimulation results 214 based on an amount of data 218 in the functionoutput of the particular simulation result 212 and/or an amount of time220 used by server simulation 210 to generate the particular simulationresult 212. For example, it may be inefficient to send results 212 toclient device 202 that use relatively little time to compute and/or arerepresented by a relatively large amount of data, as such results may beefficiently simulated on client device 202, and may utilize anundesirable amount of bandwidth if sent from server system 204.Likewise, results 212 that utilize a greater amount of time to compute,yet are represented by a relatively small amount of data, may bewell-suited for simulation on the cloud-based service, as such resultswould benefit from the greater computing resources of server system 204yet utilize relatively little bandwidth.

Server system 204 may provide the selected simulation results 214 toclient device 202 for storage in a lookup structure 222. At any giventime, lookup structure 222 may therefore comprise one or more simulationresults 224 received from server system 204.

During execution of client simulation 208, client device 202 may beconfigured to interact with lookup structure 222 in order to determine(e.g. upon occurrence of a function call) if lookup structure 222includes a particular result 224. If the lookup structure includes theparticular result 224 (e.g. a result corresponding to a particularfunction and set of inputs for the function), the result may be utilizedby client simulation 208 in lieu of computing the result locally onclient device 202. It will be appreciated that retrieving a result fromthe lookup structure 222 may increase performance of client simulation208 versus determining the result locally.

On the other hand, as mentioned above, if lookup structure 222 does notinclude a particular result 224, client device 202 may be configured tocompute the result locally. Such a scenario may occur, for example, ifserver system 204 determines (e.g., based on likelihood 216, amount ofdata 218, and/or amount of time 220) that the result is not suitable tosend to client device 202, or if results sent by the server are notreceived due, for example, to network problems.

The results sent from server system 204 may take any suitable form andbe stored in any suitable data structure or structures. For example, asone non-limiting example, the server results may be “memoized.”Memoization is a term that signifies storing, and subsequentlyutilizing, a previously computed result in lieu of re-computing theresult. In order to determine if a given result has been previouslycomputed for given input(s), memoization techniques may comprisecomputing a hash value from the input(s) and storing said hash valuewith the computed result in a memoization table. As a hash value may berepresented by a lesser amount of data than the input from which it wascomputed, it may be desirable to transmit the hash value in lieu of theinput in order to preserve network 206 bandwidth. Accordingly, in someembodiments, a hash value may be computed by server system 204 andtransmitted to client device 202 for inclusion in lookup structure 222.Similarly, the server 204 may be configured to transmit a hash valuerepresenting the computed result or one or more elements thereof, or anyother suitable representation of results. It will be appreciated thatother memoization techniques may employ other methods of representinginputs than the computation of hash values.

Such a memoization scheme may be implemented by utilizing markedfunction calls that memoize inputs and results in the simulations.Further, existing programs may be adapted for such a scheme simply byreplacing function calls marked function calls to implement memoization.For example, a function call of the form:

Entity.Update(dt)

may be replaced with a “marked” function call of the form

CloudMemoize(CEntity::Update, Entity, dt).

When a marked function is called on the client, the memoization table isreferenced to determine if the memoization table includes apreviously-computed return value for the input. Likewise, when a markedfunction is called on the cloud-based server simulation, the amount ofdata 218 in the return value and the execution time of the function 220may be recorded for use in computing a return value cost metric for usein determining whether or not to send the results to the client.

Additional information may be obtained via a memoization function callby noting the identification of the object (“mId”) on which the functionis being executed, as follows.

CloudMemoize(Entity->mId, CEntity::Update, Entity, dt).

The function and mId may be used to create a unique computationidentifier. This may allow the memoizer to differentiate results basedon the object on which the function is being executed. As each input isreceived from the client and the digital experience is resimulated, thecloud-based service may create a record of how predictable functioncalls on particular objects are by tracking how often resimulationproduces the same result, as described above.

The predictablility metric may then be combined with the return valuecost metric to create an overall score for the objects result. When aparticular frame is then at some distance ahead of the local simulation,the memoization result table on the cloud-based service may be sorted bythe score computed to identify results to be sent to the client. It willbe noted that such a system may be configured to stop sending data tothe client when a per frame bandwidth allowance is reached. This mayallow the system to utilize the entire connection when available whilealso being able to limit bandwidth use to preserve resources other data(e.g. voice) where appropriate.

It will be understood that the same marked code may be executed on boththe client and the cloud-based service. In such embodiments, the codemay determine whether it is being executed on the server or client, andthen determine the score values if it is running on the cloud-basedservice. Likewise, code on the client may run in a mode such that itreads from the memoization table but does not write to the memoizationtable when executing marked function calls.

It will be understood that any other suitable factors may be used indetermining which simulation results to send to the client device. Forexample, in some embodiments, code may be used to mark various objectsas unpredictable, such as objects located close to parts of the gamethat are directly affected by the player. This may help to avoid sendingresults to the client for such objects, as such objects may change inresponse to user actions. Marking objects as unpredictable may help tohandle situations such as where a player who has been inactive forlonger than the presimulation window suddenly takes an action thatinvalidates several frames of data that have been sent from the server.

FIG. 3 shows a process flow depicting an embodiment of a method 300 forproviding predictive cloud-based presimulation. Method 300 comprises, at302, receiving an input of state from a client device executing a clientsimulation. As mentioned above, an input of state may be received fromthe client device in response to a user input received by the clientdevice, or upon any other suitable triggering event.

The input of state received at 304 may comprise a temporal identifier304 indicating a temporal location of the state within the clientsimulation (e.g., client simulation 208). For example, in someembodiments, temporal identifier 304 may comprise a frame number. Itwill be appreciated that temporal indicator 304 may comprise anysuitable information configured to associate the input of state with alocation in the client simulation.

At 306, method 300 comprises executing a server simulation of a digitalexperience based on the input of state, the server simulation configuredto run concurrently with, and ahead of, the client simulation on theclient device. Executing the server simulation may comprise, at 308,reinitializing the server simulation at the temporal location. In otherwords, the server simulation may “rewind” to the temporal location andrestart the simulation using the input of state at that location, thushelping to ensure that server simulation results are relevant to theclient simulation. The server simulation may then re-simulate apredetermined amount into the future, for example, by executing at anaccelerated rate versus the client simulation. The server simulation maybe configured to run at any suitable amount of time ahead of the clientsimulation. Examples include, but are not limited to, times of up to twoseconds. A more specific non-limiting example of a range of timescomprises times between 500 milliseconds and one second. Such times maybe suitable in light of the latencies common with 3G cellular phones aswell as game consoles. It will be appreciated that simulating fartherahead of the client may help to ensure that the client receives theresults in time to use them, but also increases a risk that the resultsmay no longer be relevant and therefore may be re-simulated.

At 310, method 300 comprises generating a plurality of simulationresults from the server simulation. At 312, method 300 comprises, foreach result, determining a likelihood that the client simulation willuse the result. This likelihood may be determined in any suitablemanner, such as via statistics regarding the outcome of re-simulatingprevious simulation results. It will be understood that suchre-simulation results may be tracked based upon information such as anidentification of a function that produces the results, inputs to thefunction, an object acted upon by the function, and/or any othersuitable information.

Method 300 further comprises, at 314, selecting one or more simulationresults (e.g., simulation results 214) from the plurality of simulationresults based on a likelihood the client simulation will utilize aparticular simulation result. In some embodiments, the one or moresimulation results may be further selected based on other information,such as an amount of time 316 used by the server simulation to generatethe particular simulation result, and/or an amount of data 318 in theparticular simulation result. It will be appreciated that theseembodiments are presented for the purpose of example, and that the oneor more simulation results may be selected according to any othersuitable manner without departing from the scope of the presentdisclosure.

As described above, the use of an object identifier may providefunction-and-object-level granularity in analyzing the simulationresults to determine the one or more results to provide to the client.For example, referring to the example digital experience 100 of FIG. 1,a function may be configured to calculate damage/injury to variouselements of experience 100. Executing such a function may use moreresources when acting on element 108 (tank) than on the element 106(tree). As such, it may be determined to execute the function locally atthe client device when acting on the tree, but via the remote servicewhen acting on the tank.

At 320, method 300 comprises sending the one or more simulation resultsto the client device. Each of the one or more simulation results maycomprise any suitable information. For example, each result maycomprise, at 322, a representation of each of a function input, acorresponding function output generated by a function based on thefunction input and a function identifier, wherein the representation maytake any suitable form. For example, as discussed above in reference toFIG. 2, a hash value may be computed by the server system representingthe simulation results or one or more elements thereof. It will beappreciated that other representations are possible without departingfrom the scope of the present disclosure. In some embodiments, at 324,each of the one or more simulation results may further comprise anobject identifier indicating an object (e.g., tank element 108 ofdigital experience 100) acted on by the function. The use of a functionidentifier may allow the likelihood of a simulation result being used tobe determined on a more granular level than where an object identifieris not utilized. Further, in some embodiments, each of the one or moresimulation results may comprise a frame number to which that simulationresult is linked. It will be understood that said information isintended to be non-limiting, and that simulation results may compriseadditional and/or different information.

FIG. 4 shows a process flow depicting an embodiment of a method 400 forexecuting a client simulation of a digital experience utilizingpredictive cloud-based presimulation. Method 400 comprises, at 402,executing the client simulation. At 404, method 400 comprises receivingone or more simulation results from a server system executing a serversimulation (e.g., server simulation 210) concurrently with, and aheadof, the client simulation. The simulation results may comprise anysuitable information. For example, as indicated at 406, in someembodiments each of the simulation results may comprise a representationof each of a function input, a corresponding function output generatedby a function based on the function input, and a function identifier.Further, as indicated at 408, in some embodiments each simulation resultmay further comprise an object identifier indicating an object acted onby the function.

At 410, method 400 comprises storing the one or more simulation resultsin a lookup structure (e.g., lookup structure 222). Next, at 412, method400 comprises receiving a user input that affects the client simulation.At 414, method 400 comprises sending a state representing the clientsimulation after the user input to the server system. As mentionedabove, said state may be utilized to reinitialize the server simulation.It will be understood that such user inputs may be received continuallyduring execution of the digital experience.

At 416, method 400 comprises, upon occurrence of a function call,determining a corresponding simulation result for the function call isstored in the lookup structure. For example, the client simulation maycomprise marked function calls configured to produce interaction withthe lookup structure. In some embodiments, determining if the lookupstructure includes a corresponding simulation result may comprise, at418, providing a query comprising the function identifier and thefunction input for the function call. It will be understood that thesescenarios are presented for the purpose of example, and that determiningif the lookup structure includes a corresponding simulation result maybe accomplished via any suitable mechanism or combination of mechanisms.

If the lookup structure includes the corresponding simulation result,method 400 retrieving the corresponding simulation result from thelookup structure at 420. Method 400 further comprises, at 422, providinga function output from the corresponding simulation result to the clientsimulation. In other words, if the lookup structure includes acorresponding simulation result, method 400 comprises utilizing theresult without re-computing the result. On the other hand, it isdetermined at 416 that the lookup structure does not include acorresponding simulation result, method 400 comprises executing thefunction call at 424.

The simulations results received by the client device may be stored forany suitable length of time. For example, where the simulation resultsare linked to a specific frame of the digital experience, the simulationresults may be expunged after passage of that frame. In otherembodiments, the simulation results may be expunged at any othersuitable time.

In some embodiments, the above described methods and processes may betied to a computing system including one or more computers. Inparticular, the methods and processes described herein may beimplemented as a computer application, computer service, computer API,computer library, and/or other computer program product.

FIG. 5 schematically shows a nonlimiting computing system 500 that mayperform one or more of the above described methods and processes. Clientdevice 202 and server system 204 of FIG. 2 are non-limiting examples ofcomputing system 500. Computing system 500 is shown in simplified form.It is to be understood that virtually any computer architecture may beused without departing from the scope of this disclosure. In differentembodiments, computing system 500 may take the form of a mainframecomputer, server computer, desktop computer, laptop computer, tabletcomputer, home entertainment computer, network computing device, mobilecomputing device, mobile communication device, gaming device, etc.

Computing system 500 includes logic subsystem 502 and data-holdingsubsystem 504. Computing system 500 may optionally include displaysubsystem 506, communication subsystem 508, and/or other components notshown in FIG. 5. Computing system 500 may also optionally include userinput devices such as keyboards, mice, game controllers, cameras,microphones, and/or touch screens, for example.

Logic subsystem 502 may include one or more physical devices configuredto execute one or more instructions. For example, the logic subsystemmay be configured to execute one or more instructions that are part ofone or more applications, services, programs, routines, libraries,objects, components, data structures, or other logical constructs. Suchinstructions may be implemented to perform a task, implement a datatype, transform the state of one or more devices, or otherwise arrive ata desired result.

The logic subsystem may include one or more processors that areconfigured to execute software instructions. Additionally oralternatively, the logic subsystem may include one or more hardware orfirmware logic machines configured to execute hardware or firmwareinstructions. Processors of the logic subsystem may be single core ormulticore, and the programs executed thereon may be configured forparallel or distributed processing. The logic subsystem may optionallyinclude individual components that are distributed throughout two ormore devices, which may be remotely located and/or configured forcoordinated processing. One or more aspects of the logic subsystem maybe virtualized and executed by remotely accessible networked computingdevices configured in a cloud computing configuration.

Data-holding subsystem 504 may include one or more physical,non-transitory, devices configured to hold data and/or instructionsexecutable by the logic subsystem to implement the herein describedmethods and processes. When such methods and processes are implemented,the state of data-holding subsystem 504 may be transformed (e.g., tohold different data).

Data-holding subsystem 504 may include removable media and/or built-indevices. Data-holding subsystem 504 may include optical memory devices(e.g., CD, DVD, HD-DVD, Blu-Ray Disc, etc.), semiconductor memorydevices (e.g., RAM, EPROM, EEPROM, etc.) and/or magnetic memory devices(e.g., hard disk drive, floppy disk drive, tape drive, MRAM, etc.),among others. Data-holding subsystem 504 may include devices with one ormore of the following characteristics: volatile, nonvolatile, dynamic,static, read/write, read-only, random access, sequential access,location addressable, file addressable, and content addressable. In someembodiments, logic subsystem 502 and data-holding subsystem 504 may beintegrated into one or more common devices, such as an applicationspecific integrated circuit or a system on a chip.

FIG. 5 also shows an aspect of the data-holding subsystem in the form ofremovable computer-readable storage media 510, which may be used tostore and/or transfer data and/or instructions executable to implementthe herein described methods and processes. Removable computer-readablestorage media 510 may take the form of CDs, DVDs, HD-DVDs, Blu-RayDiscs, EEPROMs, and/or floppy disks, among others.

It is to be appreciated that data-holding subsystem 504 includes one ormore physical, non-transitory devices. In contrast, in some embodimentsaspects of the instructions described herein may be propagated in atransitory fashion by a pure signal (e.g., an electromagnetic signal, anoptical signal, etc.) that is not held by a physical device for at leasta finite duration. Furthermore, data and/or other forms of informationpertaining to the present disclosure may be propagated by a pure signal.

The terms “module,” “program,” and “engine” may be used to describe anaspect of computing system 500 that is implemented to perform one ormore particular functions. In some cases, such a module, program, orengine may be instantiated via logic subsystem 502 executinginstructions held by data-holding subsystem 504. It is to be understoodthat different modules, programs, and/or engines may be instantiatedfrom the same application, service, code block, object, library,routine, API, function, etc. Likewise, the same module, program, and/orengine may be instantiated by different applications, services, codeblocks, objects, routines, APIs, functions, etc. The terms “module,”“program,” and “engine” are meant to encompass individual or groups ofexecutable files, data files, libraries, drivers, scripts, databaserecords, etc.

It is to be appreciated that a “service”, as used herein, may be anapplication program executable across multiple user sessions andavailable to one or more system components, programs, and/or otherservices. In some implementations, a service may run on a serverresponsive to a request from a client.

When included, display subsystem 506 may be used to present a visualrepresentation of data held by data-holding subsystem 504. As the hereindescribed methods and processes change the data held by the data-holdingsubsystem, and thus transform the state of the data-holding subsystem,the state of display subsystem 506 may likewise be transformed tovisually represent changes in the underlying data. Display subsystem 506may include one or more display devices utilizing virtually any type oftechnology. Such display devices may be combined with logic subsystem502 and/or data-holding subsystem 504 in a shared enclosure, or suchdisplay devices may be peripheral display devices.

When included, communication subsystem 508 may be configured tocommunicatively couple computing system 500 with one or more othercomputing devices. Communication subsystem 508 may include wired and/orwireless communication devices compatible with one or more differentcommunication protocols. As nonlimiting examples, the communicationsubsystem may be configured for communication via a wireless telephonenetwork, a wireless local area network, a wired local area network, awireless wide area network, a wired wide area network, etc. In someembodiments, the communication subsystem may allow computing system 500to send and/or receive messages to and/or from other devices via anetwork such as the Internet.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. As such, various acts illustrated may beperformed in the sequence illustrated, in other sequences, in parallel,or in some cases omitted. Likewise, the order of the above-describedprocesses may be changed.

The subject matter of the present disclosure includes all novel andnonobvious combinations and subcombinations of the various processes,systems and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

The invention claimed is:
 1. A computing device, comprising: a logic subsystem comprising a processor; and a data-storage subsystem comprising memory having instructions executable by the processor to receive an input of state from a client device, execute a server simulation of a digital experience based on the input of state, the server simulation configured to run concurrently with, and ahead of, a client simulation of the digital experience being executed on the client device, generate a plurality of simulation results from the server simulation, determine, for each simulation result, a likelihood that the client simulation will utilize the simulation result, select one or more simulation results from the plurality of simulation results based on the likelihood, for each selected simulation result, that the client simulation will utilize the selected simulation result, and send the one or more selected simulation results to the client device.
 2. The computing device of claim 1, wherein the instructions are further executable to select the one or more simulation results based on an amount of time used by the server simulation to generate each of the one or more selected simulation results.
 3. The computing device of claim 1, wherein the instructions are further executable to select the one or more simulation results based on an amount of data in a function output of each of the one or more selected simulation results.
 4. The computing device of claim 1, wherein each of the one or more simulation results sent to the client device comprises a representation of each of a function input, a corresponding function output generated by a function based on the function input and a function identifier.
 5. The computing device of claim 4, wherein each of the one or more simulation results sent to the client device further comprises an object identifier indicating an object acted on by the function.
 6. The computing device of claim 1, wherein the input of state comprises a temporal identifier indicating a temporal location of the state within the client simulation.
 7. The computing device of claim 6, wherein the temporal location comprises a frame number.
 8. The computing device of claim 7, wherein the instructions are executable to execute the simulation by reinitializing the server simulation at the temporal location.
 9. The computing device of claim 1, wherein the instructions are further executable to determine the likelihood based on one or more statistics regarding re-simulation of previous simulation results.
 10. The computing device of claim 1, wherein the instructions are executable to execute the simulation at a higher quality than the client simulation on the client device.
 11. A computer-readable memory device excluding a propagating signal per se, the computer readable memory device comprising instructions stored thereon that are executable by a computing device to receive one or more simulation results from a server system executing a server simulation of the digital experience concurrently with, and ahead of, the client simulation being executed at the computing device, each of the simulation results comprising a function input, a corresponding function output generated by a function based on the function input, and a function identifier, store the one or more simulation results in a lookup structure; upon occurrence of a function call, determine if the lookup structure includes a corresponding simulation result for the function call, if the lookup structure includes the corresponding simulation result, retrieve the corresponding simulation result from the lookup structure and executing the client simulation using the corresponding simulation result retrieved from the lookup structure, and if the lookup structure does not include the corresponding simulation result, execute the function call.
 12. The computer-readable memory device of claim 11, wherein the instructions executable to determine if the lookup structure includes the corresponding simulation result for the function call by providing to the lookup structure a query comprising the function identifier and the function input for the function call.
 13. The computer-readable memory device of claim 11, wherein the instructions are further executable to receive a user input that affects the client simulation, and send a state representing the client simulation after the user input to the server system.
 14. The computer-readable memory device of claim 11, wherein the instructions are further executable to provide a function output from the corresponding simulation result to the client simulation.
 15. The computer-readable memory device of claim 11, wherein the instructions are executable to execute the client simulation at a lower quality than the server simulation on the server system.
 16. The computer-readable memory device of claim 11, wherein each of the simulation results received from the server system further comprises an object identifier indicating an object acted on by the function.
 17. A computing device, comprising: a logic subsystem comprising a processor; and a data-storage subsystem comprising memory having instructions executable by the processor to receive an input of state from the client device, execute a server simulation of a digital experience based on the input of state, the simulation configured to run concurrently with, and ahead of, a client simulation of the digital experience being executed on the client device, generate a plurality of simulation results from the server simulation, determine, for each of the plurality of simulation results, a likelihood the client simulation will utilize a particular simulation result, the likelihood based on one or more statistics regarding re-simulation of previous simulation results, select one or more simulation results from the plurality of simulation results based on the likelihood the client simulation will utilize a particular simulation result, and send the one or more simulation results to the client device for providing memoization to the client simulation.
 18. The computing device of claim 17, wherein each of the one or more simulation results comprises a function input, a corresponding function output generated by a function based on the function input, an object identifier indicating an object acted on by the function, and a function identifier.
 19. The computing device of claim 17, wherein the instructions are executable to select the one or more simulation results based on one or more of an amount of time used by the server simulation to generate the particular simulation result and an amount of data in the function output of the particular simulation result.
 20. The computing device of claim 17, wherein each of the one or more simulation results comprises a representation of each of a function input, a corresponding function output generated by a function based on the function input and a function identifier. 